Object texture 1 pixel lines on some sides of model
As mentioned by Mr Zak Cube mapping is the correct way, have in mind however that Blender's OpenGL rendering engine does not support displaying of automatic cube mapped generated texture coordinates directly in the viewport or game engine, it always displays as a 2D mapped texture stretched on the sides.

When you render your images however, it will display correctly.

If you plan on using the OpenGL render or the game engine you will have to unwrap as generated or automatic cube texture coordinates are not currently supported.

For cycles render engine you can use object or generated texture coordinates, but again there is no support for previewing on the viewport, except for basic UV Mapped textures